1. Field of the Invention
The present invention relates to Identification Friend or Foe (IFF) systems, but more specifically, it relates to a 360.degree. IFF video resynchronizer unit for backing up and/or replacing interrogator subsystems of the IFF systems.
2. Description of the Prior Art
Identification Friend or Foe (IFF), as a technique for recognizing friendly entities, has long been a vital factor in tactical operations. IFF techniques have progressed from the recognition of coats of arms and flags to the present day electronic systems. Present day IFF systems comprise interrogator subsystems and transponder subsystems. The most important function of an interrogator subsystem is to ask the question of all unknown entities, "Who are you?". The most important function of a transponder subsystem is to answer the foregoing. Most present day Navy ships use one interrogator subsystem for each radar system. Some present day Navy ships use up to five or more interrogator subsystems.
At the present time, no backup interrogator subsystems exist. Thus, if one of the interrogator subsystems should fail, the IFF system for that corresponding radar system would not exist. Consequently, there is a need in the prior art to be able to backup any one of the interrogator subsystems.
Moreover, when an interrogator subsystem fails, that particular subsystem must be replaced or repaired. Failure occurs frequently due to the size, weight, complexity and age of the subsystems. Therefore, a need exists in the prior art to replace interrogator subsystems with a state-of-the-art unit, such as the present invention, while reducing costs and increasing reliability. In addition, there is a need in the prior art to be able to substitute such a unit in place of an interrogator subsystem for new construction. At least one interrogator subsystem of the prior art type must be present to use the present invention in the foregoing manner.
There is one well known prior art IFF system (IFF Central System) which can be used to replace and/or substitute for new construction, but, unlike the present invention, this system can not be used to backup interrogator subsystems. Also, the IFF Central System declares targets in order to accomplish the above mentioned task(s) of replacement and/or substitution. Thus, a need exists in the prior art to accomplish the foregoing task and provide backup capability, but yet be able to process replies or returns rather than targets.
The prior art, as indicated hereinabove, includes some important advances in IFF systems. However, insofar as can be determined, no prior art IFF system incorporates all of the features and advantages of the present invention.